Tripod head



July 14, 1936. Q wrm-EL 2,047,241

TRIPOD HEAD Filed'July 21, 1933 Patented July 14', 1936 UNITED STATES PATENT OFFICE '1 -mon HEADv l' Otto Wittcl, Rochester, N. Y., assignor to Eastman Kodak Company,

Rochester, N. Y.,fa corporation of New York v Application July 21, 1933, 'sei-inno. 681,599

` somma. (onus-183) The present invention relates to an improvement in a tripod head construction and more particularly to a tripod head having a'plurality of members which are relatively ,rotatable about transverse axes.

It is well known to provide tripod heads for universal movement. of the supported apparatus either by use of a universal joint or arranging the members for rotation about a vertical axis and a horizontal axis. It has also been -previously known to provide tightening means for adjusting the friction drag between the various members. Such tightening means, however, are generally objectionable in that the" friction drag between l5 the members varies upon relative movement or rotation of the tripod head members with respect to each other.

The primary object of the present invention is the provision in the rotatable joint of a tripod head of a connecting means by which the friction. drag may he controlled, but will not be altered by rotation of the tripod head members with respect to each other.

Another object of the present invention is 'the provision in a tripod head of a friction drag which comprises a plurality of friction elements arranged in surface contact with each other between the relatively movable members.

v A still further object of the present invention 3 0 is the provision in a tripod head of a connecting means for varying the friction drag between relatively movable members of the tripod head and including a threaded spindle engaging a nut member which is attached to one-of the tripod headmembers so that relative rotation of said head members does'not change the relative axial positions of said spindle and nut member.

Other and further objects of the present invention will be suggested to those skilled in the art in connection with the description of the invention with reference to the accompanying draw- The above and other objects of the invention are Yembodied in a tripod head having a pair of relatively movable members and a plurality of metal elements and friction elements alternately arranged in frictional engagement with each other and with vsaid members, in combination 50 with a threaded connection having one 'part attached to one of said movable members whereby the friction drag between said friction elements does not vary upon relative rotation of said movable members. 55 Reference is hereby made to the drawing in on the line 2-2 of Fig. 1.

which similar reference characters designate simiiar elements and in which:

Fig. 1 is a side elevation of the tripod head according to the invention with a partial section for better illustration of the differential tightening means for the vertical axis. l

Fig. 2 is a. plan view of the tripod head aecording to the invention with a partial section taken Fig. 3 is a cross section through'plates I0 and I8 and through nut member 29 particularly to illustrate the interengagement 'between vpiny I'lv on head plate I0 and notch 2l in `nut member 20; In the illustrated embodiment of the invention, the tripod head is composed of three principal members which may be taken in pairs, the members of each pair being movable with respect to each other about an axis. A head plate I0 is pro-J vided with a plurality of bearings II for engagement with the trunnions I2'- of the head-I3 on leg I4. The head plate III is provided with an axial opening I5 which has a threaded portion I6. A

pin I1 is mounted in headplate I0 and extends into said axial opening IS in a vertical position for a purpose that will be later described.

The top plate I8 is also provided with an axial opening I9. A nut member 20, located within axial openings I5 and I9, is provided with ya, notch v 2|-, see Fig. 3, which isadapted to receive the pin I1 of head plate I0, and is provided with a thread- 30 ed portion 22 which is'of the same hand but of dierent pitch from the threaded portion I6 on the head plate I0.

A plurality of friction elements are arranged in surface contact with each other between head plate Ill` and top plate I8. These friction elements may comprise a metal disk 23 which is located between head plate I0 and top plate I8 and may comprise a. pair of friction disks 24, one of which is located between head plate I0 and metal disk 23 and the other of which is located between metal disk 23 and topy plate I8. 'I'he friction disks 2l maybe composed of any suitable friction material, such as ber, leather, or rubber compov 45 sition, but fiber is preferred. v

A spindle 25 has a threaded portion 26 which corresponds to the threaded portion 'Il of head plate Illand has a threadedy portion 21 which is of the same hand but diilerent pitch from threaded portion 26 and which corresponds to the threaded portion 22 of nut member 20.

The several members of the lower joint for the tripod'head can be readily assembled in the following manner. The spindle 2B with its threaded 55 portion 26 is completely screwed 4into the threaded bore IB of head plate Ill. The nut member 2B is then screwed onto the threaded portion 21 of the spindle by turning the nut member with respect to the spindle. When the nut member 20 has been threaded along portion 21 so that the bottom oi' nut member 20 strikes the top of pin I1, then the notch 2|` is brought into registry with pin I1 and the'spindle 25 is rotated in a lefthand direction to draw nut member 20 toward head plate I0 at a diierential rate' corresponding` to the diil'erence in pitch oi threaded portions 26 and 21. This manner oi assembling the lower joint of the tripod demonstrates the advantage of the pin and notch connection between head plate It and nut member 20 by way of facilitating assembly of the structure. Performing these operations in the reverse orderwill permit ready dismantling of the lower tripod head joint.

The connecting means between the pairs of members of the tripod for regulating the friction drag upon relative movement oi' the movable members in a pair may be provided in other forms, one of which is illustrated with respect to the joint between top plate I8 and mounting plate 28. Supports 29 and 30 are attached to top plate it and are provided with axial openings 3| and 32, respectively. ,Supporting lugs 33 and 36 are mounted in spaced relation upon the undersurface of mounting plate 25. Supporting lug 33 -has an axial hole 35 while supporting lug 3d is provided with a thread 85 of de dnite pitch and hand.

A nut member 31 is provided with a threaded portion 35 ci' the e hand but of slightly different pitch. irom the thread 35 in supporting lug 35i. A set screw 39 extends through mounting plate 23 and intonut member 51 to prevent relative movement of said nut member 51 with respect to mounting plate 2d.

A plurality of metaldisks d@ and friction disks di are alternately arranged between support 3d and supporting lug 33 and between support d@ and supporting lug 3d.

A spindle i2 has a threaded portion d3 which is adapted to engage the thread 85 'of supporting lug 5d and also has a threaded portion d5 which is adapted to engage the threaded portion 3d of nut member 31. Spindle 42 has round .portions 'i5 and #it which are adaptedY to rotate within' A boit so having a winged head 5| extends' through mounting plate 2B for the attachment of the apparatus to be supported. A guide plate 52 is adjustably attached to the side of mounting plate 28 by means oi a pair of bolts 53- which pass through slots 54 of guide plate 52. A rod 55 is threaded into mounting plate 2B and is provided wth a knob 56.

it will be noted that the advantages oi the present invention are evident from a consideration of the tightening action at either of the joints. For instance, rotation oi spindle 25 will4 cause relative movement in the same directionbetween spindle 25, head plate I 0 and top plate I8 because the threaded portions 26 and 21 of spindle 25 are of the samehand.4 However, since threaded portion 26 is of different pitch from threaded portion 21, the rate of relative move- 5 ment between spindle 25 and head plate I0 will be different than the rate of relative movement between spindle 25 and top plate I8. The difference in these rates of relative movement represents the rate at which the members are moving in an axial direction toward each other to present the diiierential tightening action for gradual increase of the friotional engagement between the metal elements and friction elements.

'Ihe differential action of the spindle may be more readily understood by a considerationv of a specific example. Assume that threaded portion I6 of head platev I0 and threaded portion 26 oi spindle 25 have a pitch so that I6 threads per inch are provided on the spindle and that the 20 threaded portion 22 of nut member 20 and 'the threaded portion 2-1 of spindle 25 have a pitch so that I8 threads per inch lare provided. Consequently, upon imparting one complete turn to spindle 25, the spindle 25 moves a distance of 25 0.0625 inch with respect to head plate I0 and a distance of 0.0555 with respect to nut member 20 and top plate I8. Since these movements are both in the same direction, head plate Ill and top plate I8 will be moved toward or away from each other by the difference or 0.007 inch, which movement could otherwise only be accomplished by the employment of threaded members having a pitch equal to 143 threads'per inch. Thus, it will be seen that a very gradual relative movement between a pair of members may be accomplished even though relatively coarse threads are used andthat the friction drag between the members may be very gradually regulated.

, The principle of the invention for delicate adjustment of the friction drag between the memhere is applicable as long as there is any difference between the pitches of the threadsused.

` Howeventhe invention is practiced to greatest advantage when there is only a slight dierence. auch as one or two threads per inch between the threads employed.

Since other modlcations of the invention may be readily designed, the present disclosure is to be construed in an illustrative sense and limited only by the appended claims.

Having now particularly described my invention, what I desire to secure by Letters Patent of the United States and what I claim is:

1. Ina tripod head, the combination with a wir of body members, and a plurality ,of friction elements between said members in surface contact with each other and with said body members, of aconnectlng means including a spindle engaging one of said body members, includinga 60 bushing for abutting the other of said body members and engaged by said spindle for axial ad'- justment with respect to said one body member, and including a connection between said bushing and said one body member to prevent relative rotation therebetween.

2. In a tripod head, the combination with a pair of body members one of which is provided with a threaded bore, and a plurality of kfriction elements between said members in surface contact with each other and with said body members. of a connecting means including a threaded spindle engaging the threadedbore of said one body member, including also a bushing abutting the other oi lsaid body members and provided with a threaded hole-for receiving said spindle. and including further a connection between said bushing and said one body member to prevent relative rotation therebetween.

3. In a tripod head, the combination with a pair ofl bodymembers one of which is provided with a threaded bore, and a plurality of friction `elements between said members, of a connecting means between said body members including a spindle in threaded engagement with the threaded bore of said one body member, including also a. bushing which is in threaded engagement with said spindle and which abuts the other body member to maintain-a predetermined axial spacing between said body members, and including further a pin and notch connection between said bushing and said one body member to prevent relative rotation but to permit axial adjustment therebetween. v

4. In a tripod head, the combination with a pair of plate members, one of which is provided with s threaded bore and the other of which is provided with an opening, and a plurality of friction elements between said members in surface contact with each other and with said plate members and each provided with a centrally located hole.ofathreadedbushing withinthe opening otsaid otherplatememberandhavingashoulder engaging the same, a threaded spindle ensald bushing and the threaded bore of said one plate member and extending through the holes oi said friction elements for varying the axial pressure of said plate members on said 5 friction elements. and a connection between said bushing and said one body to prevent relative rotation therebetween.

5. In a tripod head, the combination with a pair of body membersv each having a pair of l0 spaced supports which are provided with holes, one of said body members being provided with a slotv between the supports and having the'hole in one o! said supports threaded. and a plurality of friction elements between said supports in surl5 face contact with each other and with said supports and each provided with an axial opening, of a threaded bushing adjacent the other support of the mst-mentioned body member and connected to said body memberto move therewith, 20 and a threaded spindle engaging said threaded hole ofthe support on the mst-mentioned body member and said threaded bushing, extending through the' axial openings of said friction elementaandforvuyingtheaxialpressureon said 25 friction elements.

AcERTnsIGATE oF coRREcTioN.

'Patent No. 2,047,241. A .nl'y 14, 195e.

oTTowITTEL It is hereby certified that errorV appears in .the printed specification of the above numbered patent requiringcoxrection asl follows: Page 3., second column, line '7, claim 4, after'the word "body" insert member; and that the said Lettere Patent shouldbe read with this correction therein that the same may conform to the record of theicase in the P atent Office.'

Signed and sealed this 29th day of September, lA. D. 1936-.

l "Henry van vAttuale (Seal) i v Acting Commissioner` oiv Patents. 

